SEOUL, South Korea — Opposition leader Kim Dae Jung acknowledged Tuesday that there will be no popular uprising against government candidate Roh Tae Woo's victory in the Dec. 16 presidential election, despite opposition allegations that Roh won through fraud.

"I will recognize reality and prepare for the next election," Kim said at a press conference at the headquarters of his Party for Peace and Democracy. "Our basic policy is that during this year, to the end of December, we concentrate on investigating election fraud. Beginning next year, we will concentrate on preparing for the National Assembly election."

Before the presidential election, Kim had warned that if Roh won through fraud, the people of South Korea would rise in massive street protests that would force the ruling Democratic Justice Party out of power.

Blame Fraud for Loss

Both Kim and rival opposition leader Kim Young Sam, nominee of the Reunification Democratic Party, insist that victory was stolen from them by government cheating. Since the election, there have been protests by thousands of opposition supporters, including violent clashes between students and riot police, but there have been no demonstrations of a scale anywhere near large enough to pose a threat to the government.

The relative calm has been widely attributed to Roh's unexpectedly large 2-million-vote margin of victory, a lack of conclusive evidence of large-scale cheating and the perception that the two Kims contributed to Roh's victory by failing to field a single candidate--and thus divided the opposition vote.

Between them, the two Kims, who had earlier pledged that only one of them would run, won 54% of the vote. But they split that vote almost evenly, allowing Roh to win with 36.6%. Kim Young Sam finished second with 27.5%, while Kim Dae Jung ran third with 26.5%. Roh will succeed President Chun Doo Hwan on Feb. 25.

Kim Dae Jung charged Tuesday that the government probably would have won through vote manipulation even if the opposition had been united.

Again Apologizes to Public

"But in any case," he added, "if there had been a single opposition candidate and there was election fraud, there would have been more people out on the streets protesting now. The failure to have a unified opposition candidate was one of the reasons for failing to defeat the ruling party. I apologize to the people of Korea for that fact."

Kim Dae Jung's party outlined many of its specific allegations of fraud in a front-page advertisement placed in leading newspapers Tuesday.

Ad Lists 'Cheating' Methods

The advertisement accused the government of cheating by:

-- Switching ballot boxes. In one case at Jaechon, in Chungchongpuk province, opposition observers said they slipped objects such as residence cards into 16 ballot boxes, but when the boxes were opened for counting, only one box contained the identifying objects.

-- Manipulating computers. Government-controlled national television and a government-controlled newspaper, the Seoul Shinmun, allegedly reported some vote counts well before the actual counting had reached the level reported. This is an indication that computers were programmed to produce a predetermined result.

-- Using ghost voters. Official government statistics from 1985, adjusted for deaths since then, show that there should have been only about 25.2 million people of voting age for the Dec. 16 election, and about 300,000 of them are under legal restrictions that disqualify them from voting. Yet there were 25,873,548 registered voters in the election--meaning that there may have been nearly one million "ghost voters," it charged.

-- Abusing absentee voting. Soldiers were pressured to vote for Roh, and some ballots were switched after they were cast.

The ruling Democratic Justice Party has denied any significant cheating in the election. It has acknowledged that there may have been isolated cases of improprieties but has charged that the opposition was also guilty of improper activities.

Issue in Assembly Voting

Kim Dae Jung said that opposition charges of fraud will be a major issue in the National Assembly election. He compared Roh's situation to that of former President Richard M. Nixon shortly after the Watergate burglary.

Watergate "did not affect the (1972) presidential election," Kim said. "But still, it was pursued, and eventually it forced President Nixon from the White House. This is the same. We will pursue this in the National Assembly election. We shall never use any violence. We shall pursue this matter in an orderly, reasonable and lawful manner."

The date for the National Assembly election, and the rules under which it will be conducted, have not yet been established.

Both opposition parties have called for it to be held in April, while the Democratic Justice Party has said it wants to hold it in February, before Roh is inaugurated.